Method of forming an inflatable member

ABSTRACT

A method of forming or building up a reinforced inflatable member on a body wherein one end may be secured to the body with the other end movable relative to the body as the member is inflated, or wherein both ends of the inflatable member may be moved relative to the body as the member inflates. Also, the invention contemplates a relatively uncomplicated method of fabricating or forming an end anchorage for the ends of an inflatable member that is reinforced by a sheath within a minimum of space without sacrificing strength and which is able to withstand somewhat substantial stress or loads that may tend to try to pull out or shear the ends of the reinforced inflatable member.

l ited States atent 1 1 3,837,947 alone Sept. 24, 1974 METHOD OF FORMINGAN INFLATABLE Primary Examiner-Benjamin A. Borchelt MEMBER AssistantExaminerJ. V. Doramus [75] Inventor: Billy C. Malone, Houston, Tex.Attorney Agent or Firm-Jack Hayden [73] Assrgnee: Lynes, llnc., Houston,Tex. [57] ABSTRACT [22] Filed May 1969 A method of forming or buildingup a reinforced in- [21] Appl. No.: 820,966 flatable member on a bodywherein one end may be secured to the body with the other end movablerelative to the bo'cly as the member is inflated, or wherein both endsof the inflatable member may be moved re]. [58] Fieid 156/73 277/34ative to the body as the member inflates. Also, the inventioncontemplates a relatively uncomplicated 113/111 287/20 method offabricating or forming an end anchorage for the ends of an inflatablemember that is reinforced by a sheath within a minimum of space withoutsacri- [56] References Cited ficing strength and which is able towithstand some- UNITED STATES PATENTS what substantial stress or loadsthat may tend to try to 2,778,432 1/1957 Allen 277/34 pull out or shearthe ends of the reinforced inflatable 3,003,798 10/1961 Sandlin..287/20R member,

18 Claims, 7 Drawing Figures msmmu SHEET 10? Z 5/76/ C Mar/One INVENTORMagda/u m/e! & MaHLewA ATTORNEYS METHOD OF FORMING AN INFLATABLE 1MEMBER CROSS-REFERENCE TO RELATED APPLICATION The present method relatesto construction and structural arrangement disclosed and claimed in mycpending application for Inflatable Element filed May 12, 1969 andbearing Ser. No. 823,880, now US. Pat. No. 3,604,732.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to the method of forming an inflatable member whichmay be used as a forming mandrel, closure in a conduit, mine shaft orlateral, well bore, or other opening. Specifically, the inventionrelates to a method for forming or building up a reinforced inflatablemember on a body as well as a method of forming an end anchorage for theinflatable member which utilizes a minimum of space but which is able towithstand substantial stress tending to pull or shear the ends of thereinforced inflatable member. Also, the method of the present inventionrelates to forming an inflatable member wherein both ends of theinflatable element forming part of the inflatable member may be fixed ona body while one end of the inflatable member may be fixed on the bodyand the other end movable relative to the body or wherein both ends ofthe inflatable member may be movable relative to the body.

2. DESCRIPTION OF THE PRIOR ART While there may be other art, the priorart with which applicant is familiar is the patent to H. L. Sandlin, US.Pat. No. 3,003,798, and the patent to G. H. Allen, US. Pat. No.2,778,432. In the Sandlin patent, there is disclosed a reinforcingemploying either circumferentially spaced cables or a braided sheathwithin a resilient member; the reinforcing is anchored at its ends by apotting slurry comprising a resinous material, preferably an epoxyresin, a filler, and heat responsive polymerizing (or hardening) agentfor the resin. While the Sandlin patent discloses the use of a resin anda catalyst for hardening the resin to anchor the reinforcing ends of aninflatable member, the roughened surface of the cavity receiving thereinforcing, the hardened resin, and the filler comprises primarily thearrangement for securing the reinforcing at its ends. Also, Sandlin doesnot show an inflatable member including an inflatable element which maybe secured at both ends to a body with a surrounding reinforcing sheaththat may have either one or both of its ends movable relative to thebody.

In the Allen patent, a reinforcing sheath is disclosed comprising aplurality of strips of braided wire which is coated with rubber ornylon, and in the Allen patent, the reinforcing sheath thus formed bythe overlapping strips is retained in position against the stressestending to tear or pull the ends of the reinforcing position by means ofthe wedge cones 20 at each end of the inflatable member.

Thus, it can be seen from the Sandlin patent that since the primaryforce tending to retain the reinforcing sheath or cables of theinflatable member at each end is the hardened epoxy, filler, andcooperating roughened surface, the strength of the inflatable member issomewhat limited. Also, in larger diameter sizes, the Allen constructionis difficult to manufacture and expensive because of the necessity forclose tolerance machining on large diameter parts. Furthermore, in theAllen patent, the space required for the wedge cones to retain thecircumferentially arranged, longitudinally overlapping strips ofreinforcing in position to form the sheath can become cumbersome wherethe inflatable member increases in diameter while the space within whichit is to be used may be limited or restricted.

SUMMARY OF THE INVENTION The present invention relates to a method offorming an inflatable member with a reinforcing sheath on a body as wellas a method of forming an end anchorage for the reinforcing sheath whichutilizes a minimum of space.

The method of the present invention employs an adhesive such as by wayof example only, a resin and catalyst, such as an epoxy resin, and asuitable catalyst or hardening agent therefor; an acrylic adhesive, orother suitable adhesives, as a method of aiding in locking the ends of areinforcing sheath of an inflatable member in position along with amethod of forming the ends of the sheath to aid in locking the ends ofthe sheath within the hardened adhesive to retain the reinforcing endsin position notwithstanding substantial loads or stresses that may beapplied thereto upon inflation of the inflatable member.

Another object of the present invention is to provide a method ofbuilding up an inflatable member utilizing a void forming substance suchas by way of example only, a closed cell foam such as a closed cellurethane foam whereby a void is formed in the adhesive so that one orboth ends of the inflatable member may, after fabrication and uponinflation, move readily relative to the body upon which the inflatablemember is formed.

Another object of the present invention is to provide a method offorming a reinforced inflatable member wherein a shield is provided toaid in relative movement of portions of the inflatable member relativeto other portions as it inflates.

Still another object of the present invention is to provide a method offorming a reinforcing sheath for an inflatable member wherein the endsare anchored by an adhesive, which hardened adhesive along with thearrangement of the ends of the reinforcing sheath is able to withstandsubstantially greater-stresses and forces than the forces or stressesnecessary for shearing or pulling of the reinforcing when it is pottedat its ends in hardened resin and filler material.

A further object of the present invention is to provide a method offabricating an inflatable member on a body wherein an inflatable elementforming part of the member may be secured at both ends to the body witha surrounding reinforcing sheath that is movable at one or both endsrelative to the body upon inflation.

Other objects and advantages of the present invention will becomeapparent from a consideration of the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a one-quarter sectional viewof a body which has already been formed with bands secured theretoillustrating the first step of the method;

FIG. 2 illustrates the next steps and is a quarter sectional view of oneend of the body with parts cut away showing a resilient elementsurrounding the body and abutting against one of the back-up rings,along with means for securing or sealing the resilient element adjacentthe ring and a wrap temporarily positioned over the resilient element toconfine it for vulcanizing. It can be appreciated that the method offorming the other end of the inflatable member on the body is similar tothat shown in FIG. 2 whereby both ends of the resilient element aresecured adjacent the spaced back-up rings;

FIG. 3 is in part a quarter sectional view showing the inflatable memberafter it has been formed to the point where a shield for the end or endsof the inflatable member which are to be moved is provided between theresilient element and the reinforcing sheath, which in this figure isshown in half section. A sleeve is shown positioned over one end of thereinforcing sheath with the reinforcing extending beyond the back-upring;

FIG. 4 is a sectional view showing the inflatable member as having beenprovided with an additional shield applied adjacent the body on whichthe member is being formed with a void forming substance or materialsuch as a closed cell urethane foam positioned between the back-up ringand the second shield. Also, the sleeve is illustrated in a positionwhereby the shield and void forming substance may be inserted beneaththe reinforcing sheath;

FIG. 5 is a perspective view of one end of the body upon which theinflatable element is being formed showing, in this embodiment, theexposed ends of the reinforcing sheath and a member or anchor plateinserted between each of the overlapping circumferentially extendingreinforcing strips at their ends. It can be appreciated that suchmembers are inserted in each end of the sheath between the reinforcingstrips;

FIG. 6 is a sectional view, partly in elevation, of one end showing thesleeve in its final position surrounding the end of the reinforcingsheath formed by the strips with the member between and at the end ofeach strip and a closure member or seal between one end of the sleeveand the body; and

FIG. 7 is a sectional view, partly in elevation and partly cut away,illustrating one configuration of an inflatable member which has beenbuilt up on a body of a desired configuration and illustrates anarrangement of an inflatable member wherein one end is secured to thebody and the other end is movable relative thereto, with the inflatableelement sealably secured at each end to the body. An outer cover isshown as positioned between the sleeves and secured thereto and to thereinforcing sheath in the FIG. 7 illustration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the presentinvention will be described in detail wherein the inflatable element isformed or built up on a tubular member such as a pipe. However, it canbe appreciated that the body upon which the inflatable element is formedmay be of any desired configuration and that the body may be formed inany suitable manner to any size or diameter.

Attention is first directed to FIG. 1 wherein a body is representedgenerally by the numeral 20. It will be noted that the body is tubularin form and is of any desired longitudinal extent and diameter. Thesteps of forming the inflatable member on the body 20 will varysomewhat, depending upon the materials employed. For example, where theresilient element 27 which extends between the back-up rings 21 is to beformed from elastomer sheets or strips which are applied between themetal rings 21 by suitable means well known in the art, such as by acalendar machine, then the rings 21 will be secured to the body 20 inlongitudinal spaced relation as illustrated in FIG. 1, depending uponthe length of inflatable member desired. The rings 21 are illustrated asbeing welded on one side as at 23 to secure them in position to the body20 as shown. Since the rings 21 aid in anchoring the end portions of thereinforcing sheath to inhibit shear as will be described, in thoseinstances where the inflatable member is to be used at relatively highpressures, it is desirable that the means of securing the bands or rings21 to the body 20 be by welding; however, in some circumstances therings 21 could be secured to the body 20 by any suitable adhesive suchas by an epoxy resin and hardening agent by means well known in the art.

Where the resilient element 27 is preformed and precured to the desireddiameter of the outer surface of the body 20, such resilient element 27may be initially positioned on the body and thereafter the rings 21abutted against each end of the resilient element 27 and secured inposition. Where the resilient element 27 is prefermed and thenpositioned on the body 20 and the rings 21 thereafter positionedadjacent each end of the resilient element 27, suitable metal bands (notshown) or suitable strips of material of sufficient strength could beplaced on the outer surface of the resilient element 27 at each endthereof adjacent the bands 21 to clamp or seal the ends of the resilientelement 27 in position against the body 20.

Where the resilient element 27 is formed of elastomer and vulcanized inposition on the body 20, the tu bular body 20 may be cleaned adjacenteach ring for a suitable distance, by way of example, such as two orthree inches in width as illustrated at 22. The cleaning of the surfaceof the body 20 adjacent each ring 21 may be effected by sandblasting orby rough grinding or machining the surface to clean off all grease andforeign materials such as mill scale and other material so that asuitable bonding agent may be thereupon applied to the surface 22. Thebonding agent is any bonding agent well known to those skilled in theart so that when the elastomer sheet or strip forming the resilientelement 27 is vulcanized, the ends thereof will adhere and seal to theportion 22 of the body 20 adjacent each of the rings 21. After thebonding agent has been applied, then that portion of the body betweenthe cleaned surfaces 22 is prepared so that the raw elastomer will notadhere thereto during the vulcanizing step and to accomplish this asuitable mold release agent is employed, if necessary, which moldrelease agent is well known to those skilled in the art of handling andvulcanizing elastomer and forms no part of the present invention. Afterthe mold release agent has been applied thereto, then the temporary plug24 may be positioned within the threaded opening 25 which is formed inthe body 20 between the rings 21 as shown in FIG. 1 of the drawings, andmold release agent is applied thereto to prevent the resilient elementfrom bonding therewith. It can be appreciated that the plug 24 can besecured in position initially before the rings 21 are secured to thebody 20.

After the moldrelease agent has been applied to the outer surface of thebody between the cleaned portions 22, the elastomer sheet or strips areapplied between the metal bands to the desired thickness, which in someinstances will be rolled onto the pipe to build the resilient element upto a desired thickness such as one-quarter of an inch to one-half inchthick; however, in some instances, this thickness will vary and theforegoing is given by way of example only and is not intended as alimitation. It is desired that the thickness of the resilient element 27approximate the width of the metal rings 21, and if necessary, theelastomer can be trimmed after it has been applied to the outer surfacebetween the metal rings 21 to obtain uniform thicknes throughout itslongitudinal extent.

Where elastomer sheets or strips are used to form the resilient element27 on the body 20, suitable confining material such as nylon tape asrepresented at 28 is then wrapped on the exterior of the elastomer sheetor strip to confine it during the vulcanizing step. It can beappreciated that any tape or wrapping material normally employed toconfine the elastomer such as rubber during vulcanization may beemployed, and such material forms no part of the present invention.

Thereafter, the wrapped resilient element is subjected to vulcanizingeither by steam or dry heat, or any other suitable vulcanizing processto form or vulcanize the elastomer to the desired physical properties.

FIG. 3 diagrammatically illustrates the next step, or steps, of thepresent method which will be varied, depending upon whether both ends ofthe inflatable member are to be formed so that they are movable relativeto the body upon which the inflatable member is formed or whether onlyone end of the inflatable member is to be movable relative to the bodyupon which the inflatable member is formed with the other end beingfixed or secured to the body.

.If one or both ends of the element is to move, then it may bedesirable, or in some circumstances necessary to position a shield 30adjacent the movable end, or movable ends. After vulcanizing, theplastic wrap 28 is removed from the outer surface of the resilientelement 27, and the shield 30 then fixed in position. The shield 30 maybe formed of any suitable material to accomplish the results desired andwhich will withstand the temperatures encountered during curing of theadhesive or vulcanizing when an outer cover 60 is employed, as will bedescribed. It may be formed of a metal strip which may be, by way ofexample only, approximately 0.010 to 0.040 inch in thickness and may bewrapped over the ring 21 and extended around and along the end portionof the element 27 as shown in FIG. 3. The end 31 of the shield 30 may bebent down as shown in FIG. 3 over the ring 21 which it covers so as toretain it in the position and inhibit movement thereof. Where the shield30 is formed of a strip of material, the end 32 may overlap the end 33and the ends secured together by solder, spot welding, epoxy resin, orother adhesive. If the ends 32 and 33 do not overlap, but merely-abut,they may still be secured in the same manner. If desired, the shield 30may abut the end of ring 21 and be compressed into resilient element 27so that the surface 21a of ring 21 and the surface 30a of shield 30 arein substantially the same plane.

As shown in FIG. 3, the edge 31 is bent down continuously over the ring21; however, it could be bent down merely at spaced circumferentialintervals. As noted before, it is desirable that the shield retain itsposition as relative movement occurs between the reinforcing and the endof the resilient element 27 which is anchored or secured to the body 20,as will be described in greater detail hereinafter. The length of theshield 30 is preferably shorter than the over-all length of the sleeve42 which surrounds each end of the reinforcing sheath 34 as will bedescribed hereinafter.

As noted, if the inflatable member is to'be formed so that both of itsends are movable, then a shield 30 will be provided adjacent each of thespaced rings 21 whereas if only one of the ends of the inflatable memberis to be movable, then a shield 30 is positioned adjacent the ring 21 onthe end of the inflatable member which is movable.

If the smooth exposed surface of shield 30 is such that the adhesiveemployed, as will be described, might stick to it, then a mold releaseagent of any suitable type well known to those skilled in the art may beemployed to prevent the adhesive from sticking to the exposed surface ofthe shield 30.

The reinforcing sheath referred to generally by the numeral 34 in FIG. 3is next formed, and it can be noted that the reinforcing sheath 34 ispreferably formed of longitudinally extending strips 35 which are of asuitable length so that they extend beyond each of the rings 21, at eachend of the inflatable member--with only one of such ends beingillustrated in FIG. 3 and showingthe strips 35 extending beyond the ring21 secured to the body 20. It will be noted that each of thelongitudinally extending strips 35 circumferentially overlapan adjacentstrip. The width of the strips'and their arrangement in forming thesheath 34 is such that each of the strips will overlap the next adjacentstrip when the inflatable member is deflated and each strip will overlapthe next adjacent strip when the inflatable member is inflated, thusforming a reinforcing sheath for the inflatable element at all times.

Depending upon the use for which the inflatable member is constructed,the base material of the strips may be of flat braided wire impregnatedwith elastomer or plastic, strips of plain woven fiberglass which may ormay not be impregnated with elastomer or plastic, strips of plain orwoven nylon, strips of spring steel, strips of metal such as ordinarymild steel or other permanently deformable material (where a permanentset is desired in the inflatable member), strips of other plain or wovenmaterial, such as teflon or other plastics, depending upon the pressureto which the inflatable member is to be inflated.

As a practical matter, the strips 35 which form the reinforcing sheath34 may be laid or placed on the outer surface of the inflatable element27 in any suitable manner, and one suitable manner is to position atleast one rubber band or O-ring on the inflatable element 27 to retainthe strips 35 in position as they are applied one by one. After all ofthe strips 35 have been placed on the inflatable element 27, temporarymetal bands held in place by any suitable clamp means may be employed toretain the strips in position and prevent shifting thereof duringsubsequent forming of other portions of the inflatable member.

After the reinforcing sheath 34 has been formed, then the sleeves 42 maybe slipped over the ends of the body 20 and preferably moved to aposition as illustrated in FIG. 4 to expose not only the ends of thestrips 35 but also the metal bands or rings 21. FIG. 4 also illustratesone end of an inflatable member and the method of forming thereof, whichend is formed so that it may move relative to the body upon which theinflatable member is being formed, and it can be appreciated that ifboth ends of the inflatable member are to be movable, they will beformed in a manner similar to that described with regard to FIG. 4.

Where the end of the inflatable member is to be formed so that it ismovable, a void forming substance or material such as by way of example,a closed cell foam, such as closed cell urethane foam may be positionedto form ring 44 which abuts metal ring 21. To accomplish this, it can beappreciated that the ends of the reinforcing strips 35 may be flaredoutwardly and a strip or ring of void forming substance positioned asshown at 44 in FIG. 4. The void forming substance may be balsa wood,styrofoam, heavy grease which resists deterioration under hightemperatures (i.e., above the curing temperature of the adhesive orvulcanizing temperatures employed which are both well known to thoseskilled in the art), a thin shell of plastic, wood, metal, or othermaterial which will collapse under pressure, but which will effectivelyform a void on one side of the ring 21 so that adhesive will beprevented from filling it and thereby provide a space to accommodatemovement of the end of the inflatable member.

Where the surface 20 of body 20 is such that it will accommodatemovement of the inflatable member end, then a mold release agent can beapplied thereto to inhibit adhesive from sticking to the surface 20'. Ifnecessary, an additional shield 45 formed of a strip of material such asteflon which has a smooth surface, or metal, can be inserted beneath thereinforcing and against the outer surface 20 of the body 20. Its ends 46and 47 may be overlapped and secured as described with regard to theshield 30, or they may be abutted and setained commercially and forms nopart of the present invention.

It will be noted that the second shield 45 is in spaced relation to themetal ring 21, and if desired, the void forming substance or materialmay overlap the second shield 45 as shown in FIG. 4.

As noted previously, the void forming substance 44 is compressible andcollapses under pressure to accommodate movement of the inflatablemember end relative to the body on which is is formed.

It can be appreciated that if desired the void forming substance ormaterial 44 and the second shield 45 could be first positioned on thebody 20 and then the reinforcing strips laid over the inflatable element27 which would avoid flaring the ends of the strips 35 as previouslymentioned. Actually, whether the second shield 45 is employed or not,the void forming substance 44 may be positioned anytime before members38 are inserted in the sheath 34 as will be described.

Attention is now directed to FIG. 5 of the drawings wherein it will benoted that members or anchor plates 38 are inserted in the sheathbetween the ends of the strips 35.

As shown in FIG. 5, a member or anchor plate 38 may be inserted betweeneach of the strips 35 at each end of the sheath 34; however, such methodand arrangement is only the preferred form, and if desired, the anchorplates or members 38 may be inserted in any staggered relationship suchas between every other strip 35, or even between every third or everysixth strip, or otherwise, depending upon the strength desired in theend anchorage for the inflatable member. The arrangement shown in FIG. 5provides the strongest end anchorage for the inflatable member.

When the anchor plates 28 are inserted in the ends of the sheath, theyare loose. That is, a void is formed between the anchor plates 38 andends of strips 35 so that the adhesive employed will have intimatecontact with the exposed surfaces of members 38 and adjacent exposedends of strips 35.

Where the strips 35 are formed of a base material such as braided fibersor wire coated with elastomer or plastic, then the elastomer or plasticis preferably removed therefrom. Stripping the coating exposes the basematerial of the strips 35 so as to form a better bond with the adhesivesubstance as will be described.

Where nylon or other plastic is employed as the base material of strips35, the members 38 could be formed of nylon or other plastic. It isgenerally desirable that the strength of the members 38 approach thestrength of the base material of the strips 35 to achieve the mosteffective anchorage. As a practical matter, the members 38 areapproximately two to three inches in length, but this length may vary asdesired. Also, the members 38 may be flat or arcuate.

After the members 38 have been positioned as shown in FIG. 5 of thedrawings, then the sleeve 42 is slipped along the sheath 34 until thecounterbore 42' formed therein abuts the innermost end 38' of themembers 38 as shown in FIG. 6. If desired, the sleeves 42 can bepositioned in their final position and the members 38 then inserted inthe ends of the sheath 34. After the members 38 are inserted and thesleeve 42 properly positioned, one of the ends between the sleeves 42and the body 20 is closed off by any suitable means such as a closure orseal 50. As shown in FIG. 6, the closure 50 is a metal ring which isinserted within the counterbore 42 and thereafter may be secured to thesleeve 42 by suitable means such as welding 51. It will be noted thatthe inner edge 53 of the ring 50 rides on the shield 45, where suchshield is employed, as more clearly illustrated in FIG. 7 of thedrawings. Where no shield 45 is employed, the ring will ride on surface20' of body 20.

After the space between the sleeves 42 and the body 20 has been closedoff at one end of the sleeves 42, each end of the member may be suppliedwith a suitable adhesive for bonding the members 38 and ends of strips35. It will be noted that the sleeves 42 are each provided with a hole42a, and after the closure 50 has been secured in position, the body 20may be suspended or supported in substantially a vertical position. Itshould be noted at this point that the ring 50 at the other end of theinflatable member will either ride on a shield 45 or on the surface 20of body 20 where both ends are to be movable, or if one end is to befixed as the inflatable member is illustrated in FIG. 7 of the drawings,the ring 50' will be secured to the body 20 by a weld 54. If only oneend of the inflatable member is to be movable relative to the body uponwhich it is being formed, then the inflatable member will assume theconfiguration as shown in FIG. 7 wherein one end is completely sealedoff and the other end is partially sealed off. In order to seal off theend which is partially sealed off, that is, the movable end-suitablemeans such as the seal element represented in dotted line at 56 may beemployed to seal off between the ring 50, the shield 45, and the outersurface 20 of the body 20. Thereupon, the adhesive may be poured in theother end 42b of the sleeve, whereupon it will flow downwardly into thesleeve 42 and fill it up to the hole 42a. The adhesive may then beprecured to a partially hardened condition, whereupon the other end ofthe inflatable member is positioned so as to receive the adhesivethrough the end 42b of the outer sleeve 42. Again the sleeve is filleduntil the adhesive leaks out the hole 42a, and thereupon precured topartially harden the adhesive. Thereafter, the adhesive can be fullyhardened or cured by heating for a suitable length of time if desiredand if necessary.

The adhesive employed may be of any suitable type, one which cures atroom temperature, or one which cures more readily with applied heat. Forexample, it may be any suitable epoxy resin and catalyst, the catalystbeing well known to those skilled in the art. One suitable adhesive issold under the trademark EPON by Shell Chemical Corporation. A suitableacrylic adhesive is sold under the trademark CHEMLOK by Hughson ChemicalCompany, Division of Lord Corporation, and another suitable adhesive issold under the trademark SOLlTl-IANE by Thiokol Chemical Corporation.

It is desirable that the adhesive when fully cured provide an intimatebond with the plates 38 and ends of strips as well as being hard andremaining hard at elevated temperatures.

Where an adhesive is used that cures at room temperature, wax may beemployed as the void forming substance 44, and after the adhesive hascured, the wax could be melted and poured out the end 42b of sleeve 42.

In those situations where it is desired, an outer cover as representedat 60 of resilient or plastic material may beapplied to the reinforcingsheath 34. This is accomplished by cleaning the exposed portions of thereinforcing strips 35 to remove. grease, or other foreign material, onesuitable cleaning agent being methyl ethyl ketone, or if desired, alight sandblasting may be employed to clean the exposed surfaces andthen a bonding agent is applied to the cleaned surfaces. The temporarymetal bands on the sheath 34 are then removed.

The elastomer is then applied in sheets or strips to the reinforcingsheath 34. If desired, the elastomer may be trimmed to provide a uniformthickness. Thereafter, a

wrap (not shown) or the like is applied to the elastomer in a mannerpreviously described with regard to the resilient element 27 to confineit during vulcanizing. After the outer cover has been vulcanized, thetape or wrap is removed so that the inflatable member may expand when itis inflated.

Thereafter, the plug 24 is removed, leaving the opening 25 for receivingfluid internally of the inflatable member. If desired, the inflatablemember may be inflated so as to break the movable end or ends free tocollapse the ring or rings 44 and to assure proper functioning of theinflatable member.

The foregoing disclosure and description of. theinvention areillustrative and explanatory thereof, and various changes in the size,shape, and materials as well as in'the details of the illustratedconstruction may be made without departing from the spirit of theinvention.

What is claimed is: j

1. A method of fabricating an inflatable member on a body comprising thesteps of:

a. positioning a resilient tubular element to surround the body;

b. bonding the element adjacent each end to the body;

c. securing back-up rings on the body adjacent each end of the resilientelement;

cl. positioning reinforcing strips over the resilient element to form asheath wherein the strips forming the sheath overlap adjacent stripsthroughout their length;

e. positioning a sleeve over each end of the sheath;

f. inserting anchor plates between the ends of the reinforcing strips;

g. sealing off one end of each sleeve with closure means; and I h.pouring an adhesive mixture into the other end of each of the sleeves tobond the anchor plates and ends of the reinforcing strips.

2. A method of fabricating an inflatable member on a body comprising thesteps of:

a. positioning a resilient tubular element to surround the body;

b. bonding the element adjacent each end to the body;

c. securing back-up rings on the body adjacent each end of the resilientelement;

(1. securing a shield in position over at least one end portion of theresilient tubular element;

e. positioning a void forming substance adjacent at least one of theback-up rings and the end portion of the element having a shieldthereon;

f. positioning reinforcing strips over the resilient element to form asheath wherein the strips forming the sheath overlap adjacent stripsthroughout their length;

g. positioning a sleeve over each end of the sheath;

h. inserting anchor plates between the ends of the reinforcing strips;

i. sealing off one end of each sleeve with closure means; and

j. pouring an adhesive mixture into the other end of each of the sleevesto bond the anchor plates and ends of the reinforcing strips.

3. The method of claim 1 including the additional step of applying aresilient cover to the sheath and the sleeves.

4. The method of claim 2 including the additional step of applying aresilient cover to the sheath and the sleeves.

5. The method of claim 1 including the step of securing the end of oneof the sleeves to the body.

6. The method of claim 2 including the step of securing the end of oneof the sleeves to the body.

7. A method of fabricating an inflatable member on a tubular bodycomprising the steps of:

a. welding back-up rings on the tubular body in spaced relationship;

b. cleaning the tubular body adjacent each ring for receiving a bondingagent and applying the bonding agent to the cleaned surface;

c. applying an elastomer to the tubular body between the rings to adesired thickness;

d. applying a confining means to the elastomer on the tubular body toconfine it;

e. vulcanizing the elastomer on the body to secure it at each endadjacent the metal rings and to form a resilient element;

f. removing the confining means from the vulcanized elastomer;

g. positioning reinforcing strips over the resilient element to form asheath wherein the strips forming the sheath overlap adjacent stripsthroughout their length;

h. positioning a sleeve over each end of the sheath;

i. inserting anchor plates between the ends of the reinforcing strips;

j. sealing off one end of each sleeve with closure means; and

k. pouring an adhesive mixture into the other end of each of the sleevesto bond the anchor plates and ends of the reinforcing strips.

8. The invention of claim 7 including the steps of:

a. applying an elastomer to the sheath to a desired thickness;

b. applying a confining means to the sheath to confine it;

c. vulcanizing the elastomer on the sheath and to the sleeves; and

d. removing the confining means from the vulcanized elastomer.

9. The invention of claim 7 including the step of securing the end ofone of the sleeves to the body.

10. The method of claim 7 including the additional step of applying aresilient cover to the sheath and the sleeves.

11. The method of claim 7 wherein the tubular body has an openingtherethrough between said rings which are welded in position in spacedrelation, the additional step of plugging the opening before vulcanizingthe rubber to form the resilient element.

12. A method of fabricating an inflatable member on a body comprisingthe steps of:

a. welding back-up rings on the tubular body in spaced relationship;

b. cleaning the tubular body adjacent each ring for receiving a bondingagent and applying the bonding agent to the cleaned surface;

0. applying an elastomer to the tubular body between the rings to adesired thickness;

d. applying a confining means to the elastomer on the tubular body toconfine it;

e. vulcanizing the elastomer on the body to secure it at each endadjacent the metal rings and to form a resilient element;

f. removing the confining means from the vulcanized elastomer;

' g. securing a shield in position over at least one end portion of theresilient element;

h. positioning a void forming substance adjacent at least one of theback-up rings and the end portion of the element having a shieldthereon;

i. positioning reinforcing strips over the resilient element to form asheath wherein the strips forming the sheath overlap adjacent stripsthroughout their length;

j j. positioning a sleeve over each end of the sheath;

k. inserting anchor plates between the ends of the reinforcing strips;

1. sealing off one end of each sleeve with closure means; and

m. pouring an adhesive mixture into the other end of each of the sleevesto bond the anchor plates and ends of the reinforcing strips.

13. The invention of claim 12 including the step of securing the end ofone of the sleeves to the body.

14. The method of claim 12 wherein the tubular body has an openingtherethrough between saidrings which are welded in position in spacedrelation, the additional step of plugging the opening before vulcanizingthe rubber to form the resilient element.

15. The method of claim 12 including the additional step of applying aresilient cover to the sheath and the sleeves.

16. The invention of claim 12 including the steps of:

a. applying an elastomer to the sheath to a desired thickness;

b. applying a confining means to the sheath to conc. vulcanizing theelastomer on the sheath and to the sleeves; and

d. removing the confining means from the vulcanized elastomer.

17. A method of fabricating an end anchorage for an inflatable memberthat is reinforced by a surrounding sheath formed of strip material withsleeves surrounding each end of the sheath comprising the steps of:

a. inserting plate members in the sheath between ends of the strips;

b. sealing off one end of the sleeves with closure means; and

c. pouring an adhesive mixture into the other end of each of the sleevesfor bonding the members and the sheath.

18. A method of fabricating an end anchorage for an inflatable memberthat is reinforced by a surrounding sheath formed of strip material withat least one sleeve surrounding an end of the sheath comprising thesteps of:

a. inserting plate members in the sheath between ends of the stripsadjacent a surrounding sleeve;

b. sealing off one end of the sleeve with closure means; and c. pouringan adhesive mixture into the other end of the sleeve for bonding themembers and the sheath.

1. A method of fabricating an inflatable member on a body comprising thesteps of: a. positioning a resilient tubular element to surround thebody; b. bonding the element adjacent each end to the body; c. securingback-up rings on the body adjacent each end of the resilient element; d.positioning reinforcing strips over the resilient element to form asheath wherein the strips forming the sheath overlap adjacent stripsthroughout their length; e. positioning a sleeve over each end of thesheath; f. inserting anchor plates between the ends of the reinforcingstrips; g. sealing off one end of each sleeve with closure means; and h.pouring an adhesive mixture into the other end of each of the sleeves tobond the anchor plates and ends of the reinforcing strips.
 2. A methodof fabricating an inflatable member on a body comprising the steps of:a. positioning a resilient tubular element to surround the body; b.bonding the element adjacent each end to the body; c. securing back-uprings on the body adjacent each end of the resilient element; d.securing a shield in position over at least one end portion of theresilient tubular element; e. positioning a void forming substanceadjacent at least one of the back-up rings and the end portion of theelement having a shield thereon; f. positioning reinforcing strips overthe resilient element to form a sheath wherein the strips forming thesheath overlap adjacent strips throughout their length; g. positioning asleeve over each end of the sheath; h. inserting anchor plates betweenthe ends of the reinforcing strips; i. sealing off one end of eachsleeve with closure means; and j. pouring an adhesive mixture into theother end of each of the sleeves to bond the anchor plates and ends ofthe reinforcing strips.
 3. The method of claim 1 including theadditional step of applying a resilient cover to the sheath and thesleeves.
 4. The method of claim 2 including the additional step ofapplying a resilient cover to the sheath and the sleeves.
 5. The methodof claim 1 including the step of securing the end of one of the sleevesto the body.
 6. The method of claim 2 including the step of securing theend of one of the sleeves to the body.
 7. A method of fabricating aninflatable member on a tubular body comprising the steps of: a. weldingback-up rings on the tubular body in spaced relationship; b. cleaningthe tubular body adjacent each ring for receiving a bonding agent andapplying the bonding agent to the cleaned surface; c. applying anelastomer to the tubular body between the rings to a desired thickness;d. applying a confining means to the elastomer on the tubular body toconfine it; e. vulcanizing the elastomer on the body to secure it ateach end adjacent the metal rings and to form a resilient element; f.removing the confining means from the vulcanized elastomer; g.positioning reinforcing strips over the resilient element to form asheath wherein the strips forming the sheath overlap adjacent stripsthroughout their length; h. positioning a sleeve over each end of thesheath; i. inserting anchor plates between the ends of the reinforcingstrips; j. sealing off one end of each sleeve with closure means; and k.pouring an adhesive mixture into the other end of each of the sleeves tobond the anchor plates and ends of the reinforcing strips.
 8. Theinvention of claim 7 including the steps of: a. applying an elastomer tothe sheath to a desired thickness; b. applying a confining means to thesheath to confine it; c. vulcanizing the elastomer on the sheath and tothe sleeves; and d. removing the confining means from the Vulcanizedelastomer.
 9. The invention of claim 7 including the step of securingthe end of one of the sleeves to the body.
 10. The method of claim 7including the additional step of applying a resilient cover to thesheath and the sleeves.
 11. The method of claim 7 wherein the tubularbody has an opening therethrough between said rings which are welded inposition in spaced relation, the additional step of plugging the openingbefore vulcanizing the rubber to form the resilient element.
 12. Amethod of fabricating an inflatable member on a body comprising thesteps of: a. welding back-up rings on the tubular body in spacedrelationship; b. cleaning the tubular body adjacent each ring forreceiving a bonding agent and applying the bonding agent to the cleanedsurface; c. applying an elastomer to the tubular body between the ringsto a desired thickness; d. applying a confining means to the elastomeron the tubular body to confine it; e. vulcanizing the elastomer on thebody to secure it at each end adjacent the metal rings and to form aresilient element; f. removing the confining means from the vulcanizedelastomer; g. securing a shield in position over at least one endportion of the resilient element; h. positioning a void formingsubstance adjacent at least one of the back-up rings and the end portionof the element having a shield thereon; i. positioning reinforcingstrips over the resilient element to form a sheath wherein the stripsforming the sheath overlap adjacent strips throughout their length; j.positioning a sleeve over each end of the sheath; k. inserting anchorplates between the ends of the reinforcing strips; l. sealing off oneend of each sleeve with closure means; and m. pouring an adhesivemixture into the other end of each of the sleeves to bond the anchorplates and ends of the reinforcing strips.
 13. The invention of claim 12including the step of securing the end of one of the sleeves to thebody.
 14. The method of claim 12 wherein the tubular body has an openingtherethrough between said rings which are welded in position in spacedrelation, the additional step of plugging the opening before vulcanizingthe rubber to form the resilient element.
 15. The method of claim 12including the additional step of applying a resilient cover to thesheath and the sleeves.
 16. The invention of claim 12 including thesteps of: a. applying an elastomer to the sheath to a desired thickness;b. applying a confining means to the sheath to confine it; c.vulcanizing the elastomer on the sheath and to the sleeves; and d.removing the confining means from the vulcanized elastomer.
 17. A methodof fabricating an end anchorage for an inflatable member that isreinforced by a surrounding sheath formed of strip material with sleevessurrounding each end of the sheath comprising the steps of: a. insertingplate members in the sheath between ends of the strips; b. sealing offone end of the sleeves with closure means; and c. pouring an adhesivemixture into the other end of each of the sleeves for bonding themembers and the sheath.
 18. A method of fabricating an end anchorage foran inflatable member that is reinforced by a surrounding sheath formedof strip material with at least one sleeve surrounding an end of thesheath comprising the steps of: a. inserting plate members in the sheathbetween ends of the strips adjacent a surrounding sleeve; b. sealing offone end of the sleeve with closure means; and c. pouring an adhesivemixture into the other end of the sleeve for bonding the members and thesheath.